Thirty-day unplanned readmissions following hospitalization for atrial fibrillation in a tertiary Syrian center: A real-world observational cohort study

Abstract

Background

Atrial fibrillation (AF) is the most common arrhythmia worldwide. Data regarding 30-day readmission following index admission for AF in the developing world are poorly described.

Objectives

The study aimed to assess the rate, predictors, and trends of 30-day readmission after index admission for AF in Syria.

Methods

We included adult patients who had an index admission with AF to Latakia’s tertiary center between June 2021 and October 2023. Patients were monitored for readmission for 30 days after index discharge. Data were taken from patients’ medical notes.

Results

A total of 661 patients were included in the final analysis, of which 282 (43%) were readmitted to hospital within 30 days following index admission. Cardiac causes were the most common cause of readmission in 72% of patients, of which 60% were AF. Readmitted patients had a higher median age (62 years vs 57 years, P = .001), and there were fewer males (58% vs 51%, P = .001). In multivariate analysis, factors that independently increased 30-day readmission risk were older age (hazard ratio [HR] 1.5, 95% confidence interval [CI] 1.1–1.9), female sex (HR 1.3, 95% CI 1.02–1.4), diabetes mellitus (HR 1.7, 95% CI 1.3–2.3), and congestive heart failure (HR 2.2, 95% CI 1.7–2.9). Most cardiac readmissions happened during the first 15 days (79%).

Conclusion

Almost 1 in 2 patients were readmitted within 30 days after an index admission for AF. Female sex, advancing age, diabetes mellitus, and congestive heart failure were independently associated with an increased risk of 30-day readmission.

Key Findings.

• ▪The 30-day readmission rate of patients who had an index admission for atrial fibrillation in this Syrian center was 43%.
• ▪Female sex, advancing age, diabetes mellitus, and congestive cardiac failure were independently associated with an increased risk of 30-day readmission.
• ▪Most readmissions with cardiac causes happened within the first 15 days of index discharge.

Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide, and its prevalence in low- to middle-income countries is likely underestimated.¹ Although AF in the developed world is extensively studied, there are little data on AF demographics and management in the Middle East, with only 4 epidemiological data registries.² AF-related research in the Arab world contributed only 0.7% of the total AF research.³

Syria has been embroiled in conflict since 2011. It has been deprived of healthcare resources and funding, particularly exacerbated during the COVID-19 pandemic.⁴ As a result, less than half of its hospitals operate at usual performance, with over 50% of its healthcare workforce forced to leave due to conflict.⁵ AF management in hospitals during the current political and economic turmoil is unclear, with a lack of published inpatient outcomes and figures originating from Syrian hospitals. In the context of the resource constraints, a real-world depiction of the current AF care and observed outcomes can aid the management and allocation of resources by identifying remediable deficiencies and, more importantly, reasonable and practical solutions that could be implemented. Although recent advances in AF treatment have improved the overall symptoms and AF burden, readmission rates continue to increase and have been one of the main sources of AF-related financial pressures on healthcare economies worldwide.⁶ Particularly for Syria, following up on patients after admission related to AF is highly challenging due to limited resources and damaged infrastructure.⁵ The 30-day readmission rate and predictors of readmission have been studied in the United States, Australia, and New Zealand but not in a developing country under conflict circumstances.

This study aims to describe the characteristics of patients readmitted to Latakia’s tertiary care center after an index admission for AF.

Methods

This was a single-center retrospective observational cohort study conducted at Tishreen’s University Hospital, Latakia, Syria, between the June 1, 2021, and October 1, 2023. The study included patients over 18 years of age treated with AF as the primary diagnosis in the indexed admission. Patients under 18 years and with missing data for age and sex were excluded. Patients were followed for 30 days following discharge from their index admission for readmission. Data sources include hospital paper and electronic records. Index admission and readmission causes were decided by the medical consultant or the medical registrar after discussing the case verbally with the medical consultant.

The primary outcome of our study was 30-day readmissions. A secondary analysis was performed to explore predictors of 30-day readmission and trends in readmissions. Readmission causes were identified using the impression of the medical registrar after discussion with the medical consultant. The research reported in this article adheres to the Declaration of Helsinki. The project was conducted as a part of an audit approved by the hospital board and involved prospective analysis of retrospectively collected anonymized data (reference: 277/B). Therefore, the need for consent was waived by the hospital board.

Statistical analysis

Continuous variables are expressed as median and interquartile range (IQR). Categorical variables are expressed as count and percentage. Pearson's chi-square or Fisher's exact test was used for categorical variables between groups. Student t tests and Kruskal-Wallis tests were used to compare continuous variables between the groups depending on the normality of the distribution.

Cox regression and Kaplan-Meier models were used to investigate the relationship between readmissions and variables. We hypothesized that specific demographic characteristics and comorbidities would affect 30-day readmission probability. Therefore, a base model was constructed consisting of age and sex to assess the incremental value of comorbidities that are significantly associated with 30-day readmission. Statistically significant comorbidities in the univariate analysis were added to the base model in multivariable analysis to improve the predictability. A 2-sided P value <.05 was considered statistically significant. Statistical analysis was performed using GraphPad Prism V10.0 for Mac (GraphPad Software).

Results

Baseline characteristics

Our study included 661 consecutive patients with an index admission with AF as the primary diagnosis between June 2021 and October 2023. Among these, 282 (43%) had an unplanned readmission within 30 days after discharge (Table 1). Compared with patients who were not readmitted within 30 days of discharge, the readmitted group had more females (49% vs 36%, P = .001), older patients (median age 62 years vs 57 years, P = .001), more patients with diabetes mellitus (DM) (36% vs 16%, P = .001), more patients with ischemic heart disease (29% vs 18%, P = .001), more patients with congestive heart failure (CHF) (26% vs 13%, P < .001), and more patients with valvular heart disease (VHD) (23% vs 14%, P = .003). The median length of stay in the index admission was not different between patients who were readmitted and patients who were not (3 [interquartile range (IQR) 1–4] days vs 2 [IQR 1–3] days, P = .09).

Table 1.

Baseline Characteristics of patients with 30-day readmission vs no readmission after index admission with acute atrial fibrillation

	Overall (n = 661)	Readmission (n = 282)	No readmission (n = 379)	P value
Demographics
Age, y	60 (53–67)	62 (54–59)	57 (52–65)	.001
Male	385 (58)	143 (51)	242 (64)	.001
Cardiovascular comorbidities
Hypertension	211 (33)	93 (33)	128 (34)	.87
IHD	152 (23)	83 (29)	69 (18)	.001
DM	161 (24)	102 (36)	59 (16)	.001
Cerebrovascular disease	122 (18)	47 (17)	75 (20)	.31
CHF	120 (18)	72 (26)	48 (13)	<.001
PCI within the last year	32 (5)	15 (5)	17 (4)	.71
CABG within the last year	19 (3)	9 (3)	10 (3)	.45
Thyroid disease	24 (4)	8 (3)	16 (4)	.41
VHD	117 (18)	65 (23)	52 (14)	.003
Other comorbidities
Anemia	106 (16)	49 (17)	57 (15)	.46
Dementia	49 (7)	19 (7)	30 (8)	.65
Active malignancy	44 (7)	21 (7)	23 (6)	.53
Chronic liver failure	50 (8)	22 (8)	28 (7)	.88
Chronic lung disease	69 (10)	35 (12)	34 (9)	.16
Chronic kidney failure	53 (8)	22 (8)	28 (7)	.2

Values are median (interquartile range) or n (%).

CABG = coronary artery bypass grafting; CHF = congestive heart failure; DM = diabetes mellitus; IHD = ischemic heart disease; PCI = primary coronary intervention; VHD = valvular heart disease.

Etiologies of 30-days readmission

The most common cause of 30-day readmission was cardiac conditions (72%). Of cardiac conditions, the most found condition was AF (60%), followed by CHF (16%) and arrhythmias other than AF (10%). The most common noncardiac causes of readmission included infection (10%), pulmonary causes (6%), and bleeding complications (4%) (Figure 1).

Figure 1.

Etiologies of 30-day readmissions after atrial fibrillation. GI = gastrointestinal.

Predictors of 30-day readmission

We identified that the female sex was associated with an increased risk for readmission compared with the male sex at 30 days (63% vs 50%, P = .01). Similarly, the presence of IHD was associated with an increased risk of admission at 30 days (45% vs 61%, P = .001), DM at 30 days (49% vs 60%, P = .005), CHF at 30 days (40% vs 61%, P < .001), and VHD at 30 days (44% vs 60%, P = .001), as demonstrated by the Kaplan-Meier figures (Figure 2). Univariable Cox regression showed that older age (hazard ratio [HR] 1.4, 95% confidence interval [CI] 1.3–1.8, P = .005), female sex (HR 1.4, 95% CI 1.1–1.8, P = .01), DM (HR 1.5, 95% CI 1.1–2, P = .03), CHF (HR 2, 95% CI 1.5–2.8, P = .001), IHD (HR 1.8, 95% CI 1.3–2.7, P = .001), and VHD (HR 1.7, 95% CI 1.2–2.4, P = .001) were associated with increased probability of 30-day readmission, while multivariate analysis showed that older age (HR 1.5, 95% CI 1.1–1.9, P = .01), female sex (HR 1.3, 95% CI 1.02–1.4, P = .01), DM (HR 1.7, 95% CI 1.3–2.3, P = .001), and CHF (HR 2.2, 95% CI 1.7–2.9, P < .001) were independently associated with increased risk of 30-day readmission, as demonstrated in Table 2.

Figure 2.

Kaplan-Meier analysis regarding predictors of 30-day readmission following index admission for atrial fibrillation. CHF = congestive heart failure; DM = diabetes mellitus; IHD = ischemic heart disease; VHD = valvular heart disease.

Table 2.

Cox regression showing univariate and multivariable-adjusted predictors of 30-day readmission in patients who survived 30 days after index atrial fibrillation hospitalization

Presenting characteristic	Univariable analysis		Multivariable analysis
	HR (95% CI)	P value	HR (95% CI)	P value
Age (per 10-y increment)	1.4 (1.3–1.8)	.005	1.5 (1.1–1.9)	.01
Female (yes vs no)	1.4 (1.1–1.8)	.01	1.3 (1.02–1.4)	.01
DM (yes vs no)	1.5 (1.1–2)	.03	1.7 (1.3–2.3)	.001
CHF (yes vs no)	2 (1.5–2.8)	.001	2.2 (1.7–2.9)	<.001
IHD (yes vs no)	1.8 (1.3–2.7)	.001	1.2 (0.9–1.8)	.11
VHD (yes vs no)	1.7 (1.2–2.4)	.001	1 (0.7–1.4)	.94
Cerebrovascular disease (yes vs no)	0.9 (0.6–1.6)	.8
Hypertension (yes vs no)	1 (0.7–1.4)	.83
Index admission LOS (yes vs no)	1.1 (0.9–1.2)	.36
Active thyroid disease (yes vs no)	0.7 (0.3–1.5)	.34
PCI within the past year (yes vs no)	1.3 (0.7–2.3)	.30
CABG within the past year (yes vs no)	1 (0.5–3.1)	.90
Chronic kidney disease (yes vs no)	0.8 (0.5–1.2)	.30
Chronic liver disease (yes vs no)	1.1 (0.7–1.7)	.77
Active malignancy (yes vs no)	1.2 (0.7–2.2)	.38
Chronic lung disease (yes vs no)	1.4 (0.9–2.1)	.10
Dementia (yes vs no)	0.8 (0.5–1.6)	.57
Anemia (yes vs no)	1.2 (0.8–1.6)	.32

CABG = coronary artery bypass grafting; CHF = congestive heart failure; CI = confidence interval; DM = diabetes mellitus; HR = hazard ratio; IHD = ischemic heart disease; LOS = length of stay; PCI = primary coronary intervention; VHD = valvular heart disease.

Trends and frequencies in 30-day readmissions

Trends in readmissions of cardiac and noncardiac causes during the 30 days following index admission are demonstrated in Figure 3. Most readmissions due to cardiac causes occurred during the first 15 days (26% at 5 days, 66% at 10 days, and 79% at 15 days), while readmissions due to noncardiac causes peaked later, with 42% at 15 days and 77% at 20 days.

Figure 3.

Trends of readmission of cardiac and noncardiac causes following index admission with atrial fibrillation. Half of the readmissions due to cardiac causes happened within the first 7 days of index discharge, and 75% happened within the first 13 days following index discharge. Half of the readmissions due to noncardiac causes happened within the first 16 days of index discharge, and 75% happened within the first 20 days following index discharge.

Of the patients readmitted, 244 (87%) patients were readmitted once, whereas 26 (9%) patients and 12 (4%) patients were readmitted twice and thrice, respectively.

Discussion

This is the first study describing trends and predictors of 30-day readmission following index admission with primary AF in Syria and the Middle East. This study highlights multiple significant novel findings for the Syrian population. First, almost half the patients were readmitted after index admission, with AF with symptomatic AF being the most common readmission cause. Second, female sex, advancing age, DM, and CHF were independently associated with an increased risk of 30-day readmission. Third, most readmissions with cardiac causes happened during the first 15 days of index discharge.

As AF is known to have enormous implications on economies worldwide,⁷ and recent studies have focused on many aspects of AF, including treatment patterns, hospitalization, and readmission rates.⁸ Our 30-day readmission rate of 43% exceeds rates reported from national registries of the developed world, with 14% to 18% in 4 different U.S. registries between 1999 and 2014.8, 9, 10, 11 Our readmission rate exceeded that of the Australian and New Zealand registries between 2010 and 2015 of 10%.¹² There are no developing world data to compare with. Our higher readmission rate can be explained by the conflict in Syria since 2011, which has massively affected health infrastructure and high turnover of skilled staff in addition to an inadequate number of allied health professionals and nurses.¹³ As only 50% of hospital and primary healthcare centers are fully functional in the country,¹³ managing risk factors and following patients presenting to hospitals with acute AF after discharge is difficult.

Furthermore, access to medications during conflict has been challenging and must be addressed by international health organizations.¹⁴ Patient engagement in high-risk behaviors, mainly smoking, is well correlated with poor AF clinical outcomes.¹⁵ A recent Syrian study during the conflict showed a smoking rate of 38% in 978 participants with a mean age of 25 years, which was described as worrying in the study.¹⁶ Therefore, patient education about and addressing these AF risk factors is vital to optimize outcomes and reduce the readmission burden in resource-depleted settings such as Syria.

Although there were no data before the conflict, supporting the Syrian healthcare system, especially primary care, would help reduce the 30-day readmission rate in Latakia and nationwide. Our cohort's most common readmission cause was cardiac conditions, of which AF was the most common cause. This was in keeping with previous literature.^8,10 Therefore, it is not highly uncommon for AF patients to be readmitted with the exact cause.¹⁷ Also, it was unusual for the Framingham study participants to find AF without recurrence in a community during the 1-year follow-up period of 1 year.¹⁸ Many AF patients have an underlying disease that is often unrecognized, and the various coexisting comorbidities could trigger AF requiring subsequent early readmissions, such as our cohort, with 9% and 4% having 2 and 3 readmissions, respectively, within the 30 days following index admission. Most cardiac readmissions happened in the first 15 days, which could be explained by our cohort's relatively high cardiovascular comorbidities, increasing the arrhythmia and heart failure risk. Variations in healthcare access, discharge planning, and care coordination could influence early readmission rates among these patients. Inadequate transition of care or limited access to specialized cardiac services may also have contributed to early readmissions.

Our study showed that a higher burden of cardiovascular disease increased the risk of 30-day readmission in keeping with the literature and came as no surprise.^7,10 Older age was associated with an increased risk of 30-day readmissions. This can be explained by the high burden of comorbidities and limited physiological reserve in the elderly population, resulting in a poorer prognosis. Females were at higher risk of readmission compared with males. The sex disparity in treatment utilization can potentially explain this.^19,20 This provides an opportunity to focus attention on underlying sociocultural mechanisms responsible for sex-specific differences and identify barriers to the delivery of effective AF treatment in Syria and the developing world. If proven effective in more extensive national studies, our model could help identify patients at a high risk of readmission, which can help guide patients' treatment during the index admission. The early readmission rate with cardiac causes can be explained by challenges in postdischarge follow-up care, including limited access to outpatient services and lack of structured follow-up programs, which can contribute to early readmissions.

Furthermore, socioeconomic disparities may affect the ability of patients to adhere to management plans and attend follow-up appointments. Financial constraints can limit access to necessary interventions and medications. It is noted that our cohort was made up of those from the developed world. Therefore, more data from the developing world are needed to help optimize outcomes in communities with limited recourses.

Limitations

Data collection was limited to a single tertiary care center in Latakia. This city was relatively less affected by the Syrian conflict than the other northern and eastern regions of Syria. Therefore, our results might not be generalizable to other centers/regions, given the significant heterogeneity in the quality and level of hospital supplies and staffing. Additionally, our analysis included only routinely collected data within the medical records and by the number of patients who presented to the hospital. Therefore, other variables potentially impacting mortality may have yet to be identified.

Conclusion

The 30-day readmission rate after index admission with primary AF was 43% in this Syrian center, exceeding other registries worldwide. Female sex, advancing age, DM, and CHF were independently associated with an increased risk of 30-day readmission. Most readmissions with cardiac causes happened within the first 15 days of index discharge, with atrial fibrillation being the most common cardiac cause of readmission. Our study supports the importance of risk factors management in preventing readmissions after index admission with AF.